10 Jun
2009
10 Jun
'09
7:16 p.m.
Hi,
On Jun 10, 2009, at 8:39 AM, Asiri Rathnayake wrote:
Hello Devs,
I have been examining Dan Miron's patches for
http://jira.xwiki.org/jira/browse/XWIKI-3313 &
http://jira.xwiki.org/jira/browse/XWIKI-2883 and they are working
fine.
However I think there are few improvements / refactorings that
should be
done before comitting the code. Most importantly, I would like us to
agree
upon the xwiki-chart api and xwiki-chart-macro format.
xwiki-chart module
==============
In dan's implementation, the chart module is actually called
xwiki-jfreechart because it is dependant on the jfreechart api.
However I
think we can extract a generic chart api from dan's implementation
without
much of a trouble. In his implementation there are three interfaces:
* ChartGenerator
* DataSource
* DataSourceFactory
* PlotFactory
Out of these interfaces only PlotFactory is dependant on jfreechart.
IMO we can construct a generic chart api by making ChartGenerator &
DataSource interfaces component roles, hiding PlotFactory in an
internal
package and getting rid of DataSourceFactory. So the final API would
be
something like:
interface ChartGenerator {
File buildChart(DataSource dataSource, Map<String, Object>
parameters, File outputDirectory)
throws ChartGeneratorException;
}
It should not return a File but an OutputStream instead. I'd call it
generate rather than build.
And remove outputDirectory. And mention it's generating an image.
so:
ChartImageGenerator.OutputStream generate(DataSource, Map);
And
interface DataSource {
// Usual tablemodel like api (from dan's implementation)
void init (params) // Initializes this datasource from the
parameters
passed in, no need of a separate factory.
}
I don't understand why it doesn't have any method.
init() doesn't seem a good method to have.
A source needs to return something. Something like a Chart definition.
We can also go to a api / implementation approach with
multiple
modules as
in:
/platform/core/trunk/xwiki-chart
|
|-> xwiki-chart-api
|
|-> xwiki-chart-jfree
But I don't know if this is worth the trouble.
It can be put in the same module for now. The jfreechart
implementation will be in the internal package as component
implementation.
xwiki-chart-macro
=============
Need more time to think about this one.
Thanks
-Vincent
Currently the chart macro has a format like:
{{chart chartType="line" source="type:XDOM;
table_number:1;range:A1-C3;series:rows" title="line
(xy_line_and_shape,
default)" width="640" height="480"/}}
I think we should change the "chartType" parameter to just "type"
and the
source parameter would be changed like:
source="<id>|<params>"
here we will use the <id> part as the component hint for the
corresponding
DataSource... and the <params> string can be anything specific for
that
DataSource (so we don't put any restrictions).
For an example, we could have a datasource named "xdom" like:
source="xdom|
document
=
Main
.WebHome
;table=someTableId;series=rows;hasHeaderRow=true;hasHeaderColumn=true"
We load the DataSource corresponding to "xdom" and let it initialize
with
the parameters string.... (that's why i put a init() method inside
DataSource component role).
The rest of the parameters would be standard : title, height, width
etc.
As a start we will have two types of DataSources: XDom and Inline
(Already
there).
This is a quite big discussion and I don't know If I have explained
myself
correctly. Please let me know what you think about this and how it
can be
improved.
Thanks a lot.
- Asiri